4,352 research outputs found
Does Less Income Mean Less Representation?
We assemble a novel dataset of matched legislative and constituent votes and demonstrate that less income does not mean less representation. We show 1) The opinions of high and low income voters are highly correlated; the legislator’s vote often reflects the desire of both. 2) What differences in representation by income exist, vary by legislator party. Republicans more often vote the will of their higher income over their lower income constituents; Democratic legislators do the reverse. 3) Differences in representation by income are largely explained by the correlation between constituent income and party affiliation.
An Analysis of Gene-Enzyme Variability in Natural Populations of Drosophila melanogaster and D. simulans
Nine populations of D. melanogaster and two populations of D. simulans were analyzed for polymorphism in 10 gene-enzyme systems by the technique of gel electrophoresis. In the eight natural populations of D. melanogaster, an average of 54% of the enzymes were polymorphic, and the average heterozygosity was 22.7%. An experimental population of D. melanogaster, which has been maintained in a laboratory cage for 20 years, showed levels of polymorphism equivalent to those of natural populations. The D. simulans populations had much less variability. The possible factors involved in maintaining these polymorphisms are discussed
An investigation of rotating stall in a single stage axial compressor
May 1955Thesis written jointly by both authors: Thesis (M.S.)--Massachusetts Institute of Technology. Dept. of Mechanical Engineering, 1955Includes bibliographical referencesThe rotating stall characteristics of a single stage axial flow compressor were investigated. The number of stall cells and their propagation velocities were found with and without stator blades. The measured velocities were compared with those predicted by Stenning's theory, assuming the downstream pressure fluctuations to be negligible, and correlation within 25% was obtained over a wide range of stall patterns. It was found that the pressure fluctuations caused by rotating stall were less downstream of the rotor than upstream; the minimum reduction across the rotor was 40% with stator blades, and 75% without stator blades. It was also found that, for the compressor tested, the stator blades decreased, the number of stall cells and tended to induce rotating stall at larger mass flow rates.National Advisory Committee for Aeronautics Contract NAw - 6375Project D.I.C. 724
On the 2-categories of weak distributive laws
A weak mixed distributive law (also called weak entwining structure) in a
2-category consists of a monad and a comonad, together with a 2-cell relating
them in a way which generalizes a mixed distributive law due to Beck. We show
that a weak mixed distributive law can be described as a compatible pair of a
monad and a comonad, in 2-categories extending, respectively, the 2-category of
comonads and the 2-category of monads. Based on this observation, we define a
2-category whose 0-cells are weak mixed distributive laws. In a 2-category K
which admits Eilenberg-Moore constructions both for monads and comonads, and in
which idempotent 2-cells split, we construct a fully faithful 2-functor from
this 2-category of weak mixed distributive laws to K^{2 x 2}.Comment: 15 pages LaTeX source, final version to appear in Comm. Algebr
First Record of a Ross\u27 Gull for Nebraska
On 17 December, 1992, we observed a Ross\u27 Gull in second-winter plumage at Sutherland Reservoir, Lincoln County. We studied the bird in detail from 7:35-10.00 a.m. and again from 11:15 a.m.-1:00 p.m. CST as it fed with several Bonaparte\u27s Gulls at the outlet between the cooling pond and the reservoir. The Ross\u27 Gull remained at this location through 28 December and was seen by many birders from around the Midwest.
During all of our observations, the small size, dark underwings, and wedge-shaped tail set this bird apart from the Bonaparte\u27s Gulls. At first, we overlooked the tail shape and tentatively identified the bird as a Little Gull. However, after studying the bird in greater detail, we noted the wedge-shaped tail and agreed that it was indeed a Ross\u27 Gull in second-winter plumage.
We estimated that the Ross\u27 Gull was about 10% smaller than a Bonaparte\u27s Gull, and had proportionately longer wings, a smaller head, and larger eyes. It had a buoyant flight, and often hovered over the water as it fed on small fish. The undersides of the flight feathers were dark gray, similar to the appearance of the underwing of an adult Little Gull. The axillars and wing linings were white. The upperwing was mostly pale gray, with clear remnants of a dark carpal bar. The carpal bar was black, and appeared as a series of spots across the secondary coverts, with a larger black spot at the base of the primaries. There was also a very broad, white trailing edge to the flight feathers, especially along the inner primaries. The mantle was also pale gray, the same color as the upperwing. The head was white except for the hint of a black collar, which appeared as a darker spot behind each eye, connected by a faint, dark line across the back of the neck
Parasitic Jaeger at Lake McConaughy
On 5 October, 1997, we joined Joel G. Jorgensen and John Sullivan for a pelagic trip on Lake McConaughy. A similar trip in late September 1996 yielded a Sabine\u27s Gull, but we were really hoping to see a jaeger. From 7:00 to 8:30 a.m. we gradually worked our way from the dam towards the western end of the lake. Besides moderate numbers of Franklin\u27s and Ring-billed Gulls, there were few birds on the lake. At approximately 8:45 a.m. Dinsmore noticed that all of the gulls at the western end of the lake had suddenly taken flight. Less than a minute later, we simultaneously spotted a jaeger soaring directly overhead. The size, dark coloration, and prominent white flashes in the Wings identified the bird as a jaeger. The bird made a couple of attacks on Franklin Gulls and then flew east down the lake. We chased the jaeger for more than ten miles before losing it. We relocated the bird a short time later just above the dam. This time, the bird attacked a couple of Ring-billed Gulls before flying west up the lake. We again took chase, but lost the bird before reaching Lemoyne.
The gull-like shape, generally brown coloration, and prominent white bases to the primaries identified the bird as a jaeger. The bird was smaller but longer-winged than a Ring-billed Gull and larger and slimmer than a Franklin\u27s Gull. The overall coloration was dark brown, except for some warmer rufous tones on the underparts. We saw no visible barring on the underparts. The bill was straight and slender, but the color pattern was not noted. The upperwing was dark brown except for white at the base of at least the outermost four primaries. The underwing was also dark except for a prominent white area on the undersides of the bases of the primaries. The rectrices were dark and the central feathers were slightly elongated with pointed tips. We all agreed on the identification as a juvenile Parasitic Jaeger. Careful size comparisons to Franklin and Ring-billed Gulls eliminated juvenile Pomarine Jaeger, which also generally shows more white color on both surfaces of the wing. Juvenile Long-tailed Jaeger was eliminated on the basis of the pattern of white on the wing and size and wing proportions. We further concluded the bird was an intermediate or dark morph individual based on the dark plumage and lack of a contrasting paler head or rump.
This represents the second accepted record of a Parasitic Jaeger for Nebraska. The only other record is of a juvenile picked up alive in Sheridan County on 23 Aug 1968 which died the next day (specimen number UNSM ZM12309) (Gates, Doris. 1969. Parasitic Jaeger rather than Skua. Nebraska Bird Review 37:31.). There are also five records of Pomarine Jaegers and a single Long-tailed Jaeger record for Nebraska. Another 16 reports are of jaegers that were not identified to species
A Regulatory Solution to Better Promote the Educational Values and Economic Sustainability of Intercollegiate Athletics
Currently there are several pending antitrust suits challenging NCAA rules restricting the economic benefits intercollegiate athletes may receive for their sports participation. Although remedying the inherent problems of commercialized college sports (primarily Division I football and men’s basketball) is a laudable objective, a free market solution mandated by antitrust law may have unintended adverse consequences. Judicial invalidation of these rules may inhibit universities from providing many athletes with a college education they would not otherwise receive, by eliminating or reducing the value of scholarships for many players whose economic value is less than the cost of an education. A wholly free market for player talent will also severely limit universities’ ability to provide academic and athletic opportunities to thousands of women and men participating in nonrevenue sports, which are funded by surplus revenues from football and men’s basketball. Rather than professionalizing college sports through antitrust litigation or unionization, we propose an open and transparent system of federal regulation combined with antitrust immunity for reforms voluntarily adopted by the NCAA. To better promote the educational values and economic sustainability of intercollegiate athletics, our proposed Congressional intercollegiate athletics reform legislation would have three mandatory requirements: 1) at least a 4-year athletic scholarship with limited university termination rights; 2) medical care or health insurance for all sports-related injuries and scholarship extensions for injuries; and 3) elimination of the NCAA requirement that Division I universities operate at least 14 intercollegiate sports. It would create an independent commission to propose non-binding intercollegiate athletics regulations. NCAA and athletic conference conduct that complies with these regulations would receive antitrust immunity
First Record of a Ross\u27 Gull for Nebraska
On 17 December, 1992, we observed a Ross\u27 Gull in second-winter plumage at Sutherland Reservoir, Lincoln County. We studied the bird in detail from 7:35-10.00 a.m. and again from 11:15 a.m.-1:00 p.m. CST as it fed with several Bonaparte\u27s Gulls at the outlet between the cooling pond and the reservoir. The Ross\u27 Gull remained at this location through 28 December and was seen by many birders from around the Midwest.
During all of our observations, the small size, dark underwings, and wedge-shaped tail set this bird apart from the Bonaparte\u27s Gulls. At first, we overlooked the tail shape and tentatively identified the bird as a Little Gull. However, after studying the bird in greater detail, we noted the wedge-shaped tail and agreed that it was indeed a Ross\u27 Gull in second-winter plumage.
We estimated that the Ross\u27 Gull was about 10% smaller than a Bonaparte\u27s Gull, and had proportionately longer wings, a smaller head, and larger eyes. It had a buoyant flight, and often hovered over the water as it fed on small fish. The undersides of the flight feathers were dark gray, similar to the appearance of the underwing of an adult Little Gull. The axillars and wing linings were white. The upperwing was mostly pale gray, with clear remnants of a dark carpal bar. The carpal bar was black, and appeared as a series of spots across the secondary coverts, with a larger black spot at the base of the primaries. There was also a very broad, white trailing edge to the flight feathers, especially along the inner primaries. The mantle was also pale gray, the same color as the upperwing. The head was white except for the hint of a black collar, which appeared as a darker spot behind each eye, connected by a faint, dark line across the back of the neck
Phospho-dependent interactions between NBS1 and MDC1 mediate chromatin retention of the MRN complex at sites of DNA damage
Mammalian cells respond to DNA double-strand breaks (DSBs) by recruiting DNA repair and cell-cycle checkpoint proteins to such sites. Central to these DNA damage response (DDR) events is the DNA damage mediator protein MDC1. MDC1 interacts with several DDR proteins, including the MRE11–RAD50–NBS1 (MRN) complex. Here, we show that MDC1 is phosphorylated on a cluster of conserved repeat motifs by casein kinase 2 (CK2). Moreover, we establish that this phosphorylation of MDC1 promotes direct, phosphorylation-dependent interactions with NBS1 in a manner that requires the closely apposed FHA and twin BRCT domains in the amino terminus of NBS1. Finally, we show that these CK2-targeted motifs in MDC1 are required to mediate NBS1 association with chromatin-flanking sites of unrepaired DSBs. These findings provide a molecular explanation for the MDC1–MRN interaction and yield insights into how MDC1 coordinates the focal assembly and activation of several DDR factors in response to DNA damage
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